The electrode mixture is used in an electrode of a non-aqueous electrolyte secondary battery or the like, and a sodium secondary battery is studied as a non-aqueous electrolyte secondary battery. Sodium that constitutes the sodium secondary battery is abundant in resources, and is an inexpensive material. The sodium secondary battery is put into practical use, whereby it is expected that a large number of large-sized power supplies can be supplied.
A sodium secondary battery usually comprises a positive electrode containing a positive electrode active material which can be doped and dedoped with a sodium ion and a negative electrode containing a negative electrode active material which can be doped and dedoped with a sodium ion, and an electrolyte.
The electrode contains a current collector and an electrode mixture placed on the current collector. In order to place an electrode mixture on a current collector, an electrode mixture paste containing and an electrode mixture and a solvent is used. The electrode mixture paste includes a material obtained by mixing and kneading an electrode active material such as a positive electrode active material and a negative electrode active material, a conductive material, a binder, and a solvent. Examples of the mixture of a binder and a solvent include organic solvent-based binders such as a solution obtained by dissolving polyvinylidene fluoride (hereinafter, may be referred to as PVdF) as a binder into an organic solvent such as N-methyl-2-pyrrolidone (hereinafter, may be referred to as NMP) as a dispersion medium (Patent Document 1).